In conventional wireless networks, multiple network nodes, such as base stations, exist in an operator cloud, where each network node acts as a cloud server. An example of such a configuration is shown in FIG. 1. The operator cloud 10 includes cloud servers 12a, 12b and 12c, referred to herein collectively as cloud servers 12. Cloud server 12a is at a base station 14a, and cloud server 12c is at a base station 14b. Base stations 14a and 14b are referred to herein collectively as base stations 14. may run a wireless device session context for one or more wireless devices 18a (WD1), 18b (WD2), 18c (WD3) and 18d (WD4), referred to herein collectively as wireless devices 18. A wireless device session context is information related to a current communication session of the wireless device, and may include pre-fetched video, web pages, emails, application session information and wireless device configuration, as well as knowledge learned via machine learning. Network elements that use the wireless device session context may be the wireless device 18 and/or the base station 14 that serves the wireless device.
When a wireless device performs a radio handover from one base station to another, as for example, from base station 14a to 14b, the wireless device session context may remain in the cloud server of origin, such as cloud server 12a, or be handed over to the destination cloud server, such as cloud server 12b. Thus, a radio handover, in which control of communications with the wireless device is passed from one base station to another, may occur with or without a wireless device session context handover. Note also that the wireless device context session may be handed over from the cloud server 12a to the cloud server 12c. Thus, upon performing the radio handover, the wireless device session context may remain at the origin base station, be transferred to the same base station to which the radio handover occurred, be handed over to a different base station, or be transferred to a network node higher in the hierarchy such as the MME 16 or even a cloud server in the application layer.
The selected target cloud server to which the session context is handed over, or whether to handover the session context at all, may depend on a tradeoff between minimization of delay and system performance. Delay in this case refers to the delay of the content being sent between the mobile device and the terminating end of the communication session and not the delay relating to the communication session setup. One approach is to always handover the wireless device session context to the base station to which the wireless device is handed over. However, if the radio handovers occur too frequently, the corresponding high frequency of occurrence of session context handovers will degrade system performance because of the utilization of bandwidth and processor load in the wireless device and the network needed to perform the session context handovers. Another approach is to limit the frequency of wireless device session context handovers. But this may result in wireless devices being further away from the current cloud server, resulting in degraded performance due to longer network delay.